Step 1
Place apples in a large pot; cover with water. Bring to a boil; reduce heat cover and simmer until apples are slightly tender about 5 minutes. Crush cooked apples and simmer for 5 more minutes.
Step 2
Transfer crushed apples to a sieve or cheesecloth. Let drip into a bowl until all liquid has drained pressing gently to release all the juice. Measure 5 cups apple juice adding water if necessary to have exact amount. Stir sugar into juice; add butter to reduce foaming.
Step 3
Bring juice mixture to a rolling boil stirring constantly. Stir in pectin; boil for exactly 1 minute to dissolve pectin stirring constantly. Remove from heat. Skim off excess foam with a metal spoon.
Step 4
Sterilize the jars and lids in boiling water for at least 5 minutes. Ladle apple jam into the hot sterilized jars filling the jars to within 1/8 inch of the top. Run a knife or a thin spatula around the insides of the jars after they have been filled to remove any air bubbles. Wipe the rims of the jars with a moist paper towel to remove any food residue. Top with lids and screw on rings.
Step 5
Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars into the boiling water using a holder. Leave a 2-inch space between the jars. Pour in more boiling water if necessary to bring the water level to at least 1 inch above the tops of the jars. Bring the water to a rolling boil cover the pot and process for 5 minutes.
Step 6
Remove the jars from the stockpot and place onto a cloth-covered or wood surface several inches apart until cool. Once cool press the top of each lid with a finger ensuring that the seal is tight (lid does not move up or down at all). Let stand at room temperature for 24 hours. Store in a cool dark area. Refrigerate opened jellies for up to 3 weeks.